Updated on 2025/03/18

写真a

 
Imai Shogo
 
Affiliation
Nippon Medical School Hospital, Clinical Imaging Center for Healthcare, Assistant Professor
Title
Assistant Professor
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Papers

  • A Case of Renal Abscess Mimicking Metastatic Lesion in a Patient with Lung Carcinosarcoma.

    Hiroya Hasegawa, Jun Akatsuka, Shogo Imai, Yuki Endo, Masato Yanagi, Hayato Takeda, Tatsuya Inoue, Yuka Toyama, Go Kimura, Yukihiro Kondo

    Journal of Nippon Medical School = Nippon Ika Daigaku zasshi   91 ( 6 )   590 - 594   2024.12

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    Renal abscesses require prompt diagnosis and appropriate intervention, as they can be life-threatening. However, diagnosis based solely on clinical findings is often challenging. We present the case of a 69-year-old woman with left renal masses on follow-up computed tomography (CT) after surgery for pT2aN0M0 lung carcinosarcoma. The masses were localized only in the left kidney without suspected metastatic lesions at other sites. The patient was referred to our department for further evaluation and treatment under a diagnosis of suspected metastatic lung carcinosarcoma of the left kidney. On enhanced CT, the left renal masses, the largest of which had a diameter of 40×36 mm had thick irregular walls gradually enhanced by the contrast media and an internal low-attenuation area. The masses showed heterogeneous signal intensity with a pseudocapsule on T2-weighted magnetic resonance imaging. Clinical symptoms such as fever or costovertebral angle tenderness were absent, and blood and urine tests were not sufficiently inflammatory to suggest a renal abscess. Histopathological findings on CT-guided renal biopsy revealed only inflammatory tissue and no tumor cells. However, because lung carcinosarcoma metastatic nodules could not be ruled out, laparoscopic left nephrectomy was performed for a definitive diagnosis and curative intent. The pathological diagnosis was renal abscess without malignant lesions. Here, we present a case of renal abscess mimicking metastatic lesions in a patient with lung carcinosarcoma. Accurately differentiating renal abscesses from metastatic renal tumors before treatment is often difficult. Renal abscess diagnosis should be considered through a comprehensive evaluation of the clinical findings of individual cases.

    DOI: 10.1272/jnms.JNMS.2024_91-609

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  • Hemodynamic Evaluation of Coronary Artery Lesions after Kawasaki Disease: Comparison of Fractional Flow Reserve during Cardiac Catheterization with Myocardial Flow Reserve during 13N-Ammonia PET. International journal

    Makoto Watanabe, Ryuji Fukazawa, Tomonari Kiriyama, Shogo Imai, Ryosuke Matsui, Kanae Shimada, Yoshiaki Hashimoto, Koji Hashimoto, Masanori Abe, Mitsuhiro Kamisago, Yasuhiko Itoh

    Journal of cardiovascular development and disease   11 ( 8 )   2024.7

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    Coronary artery lesions (CALs) after Kawasaki disease present complex coronary hemodynamics. We investigated the relationship between coronary fractional flow reserve (FFR), myocardial flow reserve (MFR), and myocardial blood flow volume fraction (MBF) and their clinical usefulness in CALs after Kawasaki disease. Nineteen patients (18 men, 1 woman) who underwent cardiac catheterization and 13N-ammonia positron emission tomography, with 24 coronary artery branches, were included. Five branches had inconsistent FFR and MFR values, two had normal FFR but abnormal MFR, and three had abnormal FFR and normal MFR. The abnormal MFR group had significantly higher MBF at rest than the normal group (0.86 ± 0.13 vs. 1.08 ± 0.09, p = 0.001). The abnormal FFR group had significantly lower MBF at adenosine loading than the normal group (2.23 ± 0.23 vs. 1.88 ± 0.29, p = 0.021). The three branches with abnormal FFR only had stenotic lesions, but the MFR may have been normal because blood was supplied by collateral vessels. Combining FFR, MFR, and MBF will enable a more accurate assessment of peripheral coronary circulation and stenotic lesions in CALs and help determine treatment strategy and timing of intervention.

    DOI: 10.3390/jcdd11080229

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  • Evaluation of Coronary Circulation by 13N-Ammonia Myocardial Perfusion Positron Emission Tomography in Patients with Right Coronary Artery Occlusion Due to Kawasaki Disease.

    Nobuko Suzuki, Makoto Watanabe, Tomonari Kiriyama, Shogo Imai, Masanori Abe, Ryuji Fukazawa, Yasuhiko Itoh

    Journal of Nippon Medical School = Nippon Ika Daigaku zasshi   91 ( 3 )   277 - 284   2024

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    BACKGROUND: Although occlusion of the right coronary artery (RCA) is common in the remote stages of Kawasaki disease, revascularization of the RCA is challenging in children and is usually managed by observation without intervention. METHODS: Using adenosine-stress 13N-ammonia myocardial perfusion positron emission tomography, we evaluated coronary circulation in 14 patients (12 males) with RCA occlusion to identify ischemia (myocardial flow ratio < 2.0) in the RCA region and examined hemodynamics, cardiac function, and coronary aneurysm diameter. These variables were also compared in patients with/without RCA segmental stenosis (SS). RESULTS: There were five cases of ischemia in the RCA region. RCA myocardial blood flow (MBF) at rest was higher in patients with ischemia than in those without ischemia, but the difference was not significant (1.27 ± 0.21 vs. 0.82 ± 0.16 mL/min/g, p = 0.2053). Nine patients presented with RCA SS, and age at onset of Kawasaki disease tended to be lower in those with SS. The maximum aneurysm diameter of RCA was significantly smaller in patients with SS (10.0 ± 2.8 vs. 14.7 ± 1.6, p = 0.0239). No significant differences in other variables were observed between patients with/without ischemia and SS. CONCLUSIONS: At rest, MBF in the RCA region was relatively well preserved, even in patients with RCA occlusion, and there was no progressive deterioration in cardiac function. Adenosine stress showed microcirculatory disturbances in only half of the patients, indicating that it is reversible in children with Kawasaki disease.

    DOI: 10.1272/jnms.JNMS.2024_91-306

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  • Estimation of Microvascular Dysfunction by Using 13N-Ammonia Positron Emission Tomography with Quantitative Myocardial Blood Flow Analysis in Chronic Coronary Syndrome.

    Shogo Imai, Tomonari Kiriyama, Koji Kanaya, Satoe Aoyama, Hitoshi Takano, Shin-Ichiro Kumita

    Journal of Nippon Medical School = Nippon Ika Daigaku zasshi   90 ( 2 )   228 - 236   2023.5

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    BACKGROUND: Although coronary artery disease (CAD) is characterized by epicardial atherosclerosis and microvascular disease, the importance of evaluating microvascular dysfunction has not been sufficiently recognized in clinical practice. We estimated microvascular disease severity by assessing hyperemic microvascular resistance (MVR), as determined by absolute quantification of myocardial blood flow (MBF) with 13N-ammonia positron emission tomography-myocardial perfusion imaging (PET-MPI). METHODS: We retrospectively collected data for 23 CAD patients who underwent both stress/rest PET-MPI and invasive coronary angiography (CAG) with fractional flow reserve (FFR) measurement. Among 30 vessels for which FFR measurement was performed, 13 had a low FFR (FFR ≤0.75). For each patient, myocardial segments of a standard 17-segment model were assigned to the stenotic myocardial area perfused by the FFR-measured vessel and a reference normal-perfusion area based on PET-MPI and the coronary distribution on CAG. Hyperemic MVR was calculated by using the formula, hyperemic MVR = hyperemic mean blood pressure × FFR/hyperemic MBF of the stenotic vessel. RESULTS: A strong negative correlation was observed between hyperemic MVR and hyperemic MBF in the reference normal-perfusion area (R = -0.758, P<0.001). CONCLUSION: Microvascular disease severity in chronic CAD can be estimated by hyperemic MBF of the normal-perfusion area with 13N-ammonia PET-MPI.

    DOI: 10.1272/jnms.JNMS.2023_90-213

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  • Peripheral Coronary Artery Circulatory Dysfunction in Remote Stage Kawasaki Disease Patients Detected by Adenosine Stress 13N-Ammonia Myocardial Perfusion Positron Emission Tomography. International journal

    Kanae Tsuno, Ryuji Fukazawa, Tomonari Kiriyama, Shogo Imai, Makoto Watanabe, Shinichiro Kumita, Yasuhiko Itoh

    Journal of clinical medicine   11 ( 4 )   2022.2

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    Coronary peripheral circulatory disturbances in the remote stage of Kawasaki disease have been reported. In this study, of the 50 patients in the remote stage of Kawasaki disease who underwent coronary perfusion evaluation using adenosine-loaded 13N-ammonia positron emission tomography, 28 patients who did not have stenosis of ≥75% in the left coronary artery underwent an evaluation for myocardial flow reserve (MFR) of the left anterior descending artery (LAD) and left circumflex artery (LCx). Clinical findings were compared between patients with normal (≥2.0) and abnormal (<2.0) MFRs. In the group with an abnormal MFR in the LAD, the responsiveness of the coronary vascular resistance to adenosine stress decreased even in the LCx (3.50 ± 1.23 vs. 2.39 ± 0.25, p = 0.0100). In the group with an abnormal MFR in the LCx, the responsiveness of the coronary vascular resistance in the LAD also decreased (3.27 ± 1.39 vs. 2.03 ± 0.25, p = 0.0105), and the age of onset of Kawasaki disease tended to be younger in the group with abnormal MFR in the LAD and LCx. We found that the peripheral coronary circulation was extensively impaired in the remote stage of Kawasaki disease, suggesting that an early onset of Kawasaki disease may affect the peripheral coronary circulation in later years.

    DOI: 10.3390/jcm11041134

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  • Myocardial T2 Mapping in Patients With Hypertrophic Cardiomyopathy. International journal

    Yasuo Amano, Fumi Yanagisawa, Masaki Tachi, Hidenobu Hashimoto, Shogo Imai, Shinichiro Kumita

    Journal of computer assisted tomography   41 ( 3 )   344 - 348   2017

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    OBJECTIVE: The aim of this study was to evaluate the usefulness of T2 mapping for detecting myocardial injuries in patients with hypertrophic cardiomyopathy (HCM). METHODS: Twenty-one HCM patients and 7 healthy volunteers were examined. The T2 values were measured at hyperintense areas (high-T2 areas) identified with T2 mapping, at late gadolinium enhancement (LGE) areas, and in nullified myocardium of the HCM patients. The associations between T2 values and laboratory data or LGE areas were assessed. RESULTS: High-T2 areas had significantly greater T2 values than LGE areas (P < 0.05) and nullified areas (P < 0.01) of HCM and normal myocardium (P < 0.01). The presence of high-T2 areas was associated with an increase in troponin T levels (P = 0.02), and T2 values correlated with the levels of brain natriuretic peptide (P = 0.036, r = 0.86). CONCLUSIONS: T2 mapping identified myocardial injuries suggested by the laboratory data in HCM.

    DOI: 10.1097/RCT.0000000000000521

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